Save as saves the file to a new path even if there was no changes

Summary:
Currently the file is not "saved as" if it hasn't been modified, which can lead to some confusion.
With this revision the file will be saved as long as the new path is different from the old one.

BUG: 364093

Reviewers: #localization, aacid, ltoscano, shaforostoff, mlaurent

Reviewed By: #localization, aacid

Tags: #localization

Differential Revision: https://phabricator.kde.org/D14699